Resonator devices with characteristic-adjusting screws have been disclosed in the below-described Patent Documents 1 to 4.
The device of Patent Document 1 uses a fixing nut with a spring washer, and the nut is engaged with a characteristic-adjusting screw. The nut is tightened by means of a rotary wrench provided with a torque-sensor, so that the nut has a torque at which the characteristic-adjusting screw can be turned to a slight degree. In this state, the characteristic-adjusting screw is tightened, and thereafter, the nut is locked.
In the device of Patent Document 2, a spring-washer becomes effective in the initial state. When a characteristic-adjusting screw is turned, a fixing nut is pressed by means of a rubber having a nut-turning piece inside thereof, so that the pressure of the spring-washer is cancelled out.
In the devices of Patent Documents 3 and 4, no fixing nuts are used. The characteristic-adjusting screw is fixed only by the spring washer.
According to the known technique disclosed in the below-described Patent Document 5, a case is burring-worked, and a characteristic-engaging screw is engaged with the burring-case.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 5-226913
Patent Document 2: Japanese Unexamined Patent Application Publication No. 7-42722
Patent Document 3: Japanese Unexamined Utility Model Registration Application Publication No. 4-64816
Patent Document 4: Japanese Unexamined Patent Application Publication No. 8-293710
Patent Document 5: Japanese Unexamined Utility Model Registration Application Publication No. 62-98307
Referring to the device of Patent Document 1, it is required to provide an angle-detecting mechanism (image sensor) for the fixing nut and the torque sensor. Thus, as a whole, the characteristic-adjusting device becomes complicate and expensive.
In the device of Patent Document 2, a plate for fixing the characteristic adjusting screw must have such strength that the plate is durable to a pressing force applied when the nut is turned. Thus, the plate needs to be thick. The nut is locked only by the action of the spring washer. Therefore, in some cases, the reliability may become doubtful.
The devices of Patent Documents 3 and 4 have the following problems: the range in which the characteristic of each device can be adjusted is restricted on the stroke of a spring-washer; and moreover, if the load is changed during adjustment, the device becomes unstable in the state that the nut is not locked.
In the device of Patent Document 5, the screw is ready to be vibrated on its axis, since only the burring is carried out. Thus, automated adjustment becomes difficult.
Generally, the above-described problems occur not only in resonator devices but also in screws which are screwed into tapped holes formed in members to be held easily and securely at predetermined insertion or extraction positions.
It is an object of the present invention to provide a screw fixing-implement which solves the above-described problems, a resonator device with the implement of which the cost is low and the characteristic-adjusting function has a high reliability, a filter, an oscillator, and a communication device each containing the resonator device, and a method of adjusting a characteristic of the resonator device.